The overall objective of Task 5, which was concluded in 2002, was to develop and verify technical requirements which will serve as the technical guidelines for grid interconnection with building integrated and other dispersed power systems. The development of these technical requirements included safety and reliable linkage to the electric grid at the lowest possible cost. The systems considered were connected to a low-voltage grid, which are typically of a size between one and fifty peak kilowatts.
On the bases of four different surveys – Existing Guidelines, Distributions Systems, Interconnection Equipment and PV Experience, four reports on the same topics were produced.
A report was issued collecting the results of the 11 important topics for grid interconnection of PV systems: Harmonics, AC-Module, Multiple inverters and AC grid, Grounding of equipment in PV systems, Ground-fault detection and array disable for PV systems, Overvoltage protection, Islanding, Electro-magnetic compatibility (EMC) of inverter, External disconnect, Re-closing and Isolation transformer and DC injection.
A report on demonstration tests using Rokko Island concerning harmonics distortion, islanding, PV output variation, DC injection etc. was produced.
This additional survey started in 1999. Reporting of PV system grid-interconnection technology, research on islanding probability and detection method, performance of high penetrated PV systems and evaluation of capacity of the PV systems have been investigated.